The present invention relates to a laundry washing machine.
More in details, the present invention relates to a front-loading home laundry washing machine provided with an internal water softening device, to which the following description refers purely by way of example without this implying any loss of generality.
As is known, currently marketed front-loading home laundry washing machines generally comprise: a substantially parallelepiped-shaped outer boxlike casing structured for resting on the floor; a substantially bell-shaped washing tub which is suspended in floating manner inside the casing, directly facing a laundry loading/unloading through opening realized in the front wall of the casing; a substantially cylindrical elastically-deformable bellows, which connects the front opening of the washing tub to the laundry loading/unloading opening formed in the front wall of the casing; a porthole door which is hinged to the front wall of the casing to rotate to and from a closing position in which the door closes the laundry loading/unloading opening in the front wall of the casing for watertight sealing the washing tub; a substantially cylindrical, bell-shaped rotatable drum structured for housing the laundry to be washed, and which is arranged inside the washing tub with its concavity facing the laundry loading/unloading opening and is supported in axially rotating manner so as to be able to freely rotate about its substantially horizontally-oriented longitudinal axis; and finally an electrically-powered motor assembly which is structured for driving into rotation the rotatable drum about its longitudinal axis inside the washing tub.
Alike any other home laundry washing machine, this type of laundry washing machine is furthermore provided with a detergent dispensing assembly which is generally located inside the boxlike casing, immediately above the washing tub, and is structured for selectively feeding into the washing tub, according to the washing cycle manually-selected by the user via a control panel generally located on the front wall of the boxlike casing, a given amount of detergent, softener and/or other washing agent suitably mixed with fresh water arriving from the water mains; and with a fresh-water supply circuit which is structured for selectively drawing fresh water from the water mains according to the washing cycle manually-selected by the user, and channelling said water to the detergent dispensing assembly or directly to the washing tub.
The detergent dispensing assembly, in turn, generally comprises: a detergent drawer which is usually divided into a number of detergent compartments each structured for being manually fillable with a corresponding detergent product, and which is fitted/inserted in manually extractable manner into a completely recessed drawer housing whose entrance is usually located on front wall of the casing, above the laundry loading/unloading opening, and whose bottom directly communicates with the inside of the washing tub via a connecting duct; and a drawer flush circuit which receives the fresh water from the fresh-water supply circuit, and is structured to selectively and alternatively channel said fresh water into any one of the detergent compartments of the detergent drawer, so as to selectively flush the detergent, softener or other washing agent out of the corresponding detergent compartment and down on the bottom of the drawer housing which, in turn, communicates with the inside of the washing tub.
As is known the hardness of the fresh water channelled into the washing tub deeply negatively influences the cleaning efficiency of the detergents and softeners used in the washing cycle, thus the user is usually requested to considerably increase, when the hardness degree of the fresh water is too high, the amount of detergent and softener used in the washing cycle and/or to mix the detergent with a given amount of very expensive, generally polycarboxylates-based, water-softening chemical product.
German patent application No. 3527047 discloses a laundry washing machine provided with an internal water softening device capable of reducing the hardness degree of the fresh water used in the pre-washing, washing and rinsing phases of the washing cycle. This water softening device is arranged upstream of the detergent dispensing assembly, and uses a ions-exchange agent to restrain the calcium and magnesium ions (Ca++ an Mg++) dissolved in the fresh water channelled to the washing tub, and the brine (i.e. salt water) to periodically regenerate this ions-exchange agent. Salt water, in fact, is able to remove from the ions-exchange agent the calcium and magnesium ions previously combined/fixed to said ions-exchange agent.
European patent application No. 1085118, in turn, discloses a front-loading home laundry washing machine wherein the internal water softening device is deeply integrated into the back of detergent dispensing assembly so as to reduce the overall production costs of the laundry washing machine.
Unluckily integration of the salt reservoir on the back of the detergent drawer causes several relevant problems. The brine accidentally coming out of the salt reservoir during drawer movement, in fact, tends to accumulate on the bottom of the drawer housing which in turn directly communicates with the upper portion of the washing tub. Thus the brine can reach quite easily the outer surface of the rotatable drum with all problems concerned. The rotatable drum, in fact, is generally made of metal material and gets rusty very quickly in presence of brine.
Furthermore, the capacity of the salt reservoir on the back of the detergent drawer is too limited for the everyday-use typical of a traditional home laundry washing machine. It is unacceptable for a normal user to refill the salt reservoir every 3-4 washing cycles.